Originally Posted by blowndart
Originally Posted by AndyF
The vent doesn't need to be very large so that is the most common mistake that people make.


The vent line needs to be large enough to allow the same volume of air to enter the tank as the volume of fuel that leaves the tank and goes to the engine (minus whatever is returned if you have a fuel return system). Otherwise you will have fuel delivery problems.




That is true but the vent line can be much smaller than the fuel line size. Fuel cells often come with a #8 vent line but the vent line doesn't need to be anywhere near that size. 1/4 inch vacuum line should be fine.